A. N. Fraga et al. describe in J. Polym. Mater. 5 (1988) 49–55 the mechanical properties from fish Gelatins as a brittle behavior characteristic of a glassy material at normal temperatures. Such a brittleness is very undesired property for a gelatin capsule.
Norland Products Inc. describe in Research Disclosure 1987, 788 that water solutions of fish gelatin remain liquid down to 10° C., wheras water solutions of animal gelatin must be heated to temperatures over 30° C. to remain liquid. This behavior of fish gelatin will not allow the use in the conventional dip moulding process at conventional temperatures because of ist to low gelling temperature.
B. Leuenberger describes in Food Hydrocolloids 1991, 353-361 viscosity and gelation properties of different mammalian and fish gelatins with the conclusion that fish gelatin may be usefull in applications where high solution viscosity without gel formation is desired.
Surprisingly it has been found that fish gelatin can be used for the production of conventional Gelatins with conventional properties by adding a setting system to the aqueous fish gelatin solution.